I'm sure there were enumerable back and forth discussions about that. Bing differentiated itself in the beginning with the large background image on the homepage as opposed to the simple colourful logo on white background that defined the Google experience.

Then Google copied the background image idea.

Now Bing has gone minimal, but there's obviously still some residual pull/desire around using imagery.

That little strip is a remnant. Like a human appendix it's a residual organ that wasn't completely eradicated as it evolved into the current design.

It's a small strip of the landing page image present on http://bing.com . Its tooltip is "Explore today's homepage". If you click on the small strip, you indeed go back to the landing page.

If you click on the bing icon, though, you also go back to the landing page.

So this little bit of refinement seems to highlight the ever-changing-landing-image as a part of the bing experience.

Probably on a linux / osx thing. I am having the same problem with firefox in Linux. props to Bing engineers for messing that up.